<title>小胖守皇宫</title><link href="http://hzoi.com/tomorrow.css" rel="stylesheet"><div class="ui existing segment"><pre><code><span class="pl-cp">#include</span> <span class="pl-cpf">&lt;bits/stdc++.h&gt;</span><span class="pl-cp"></span>
<span class="pl-k">using</span> <span class="pl-k">namespace</span> <span class="pl-n">std</span><span class="pl-p">;</span>

<span class="pl-k">typedef</span> <span class="pl-kt">long</span> <span class="pl-kt">long</span> <span class="pl-n">ll</span><span class="pl-p">;</span>
<span class="pl-k">const</span> <span class="pl-kt">int</span> <span class="pl-n">maxn</span> <span class="pl-o">=</span> <span class="pl-mi">1550</span><span class="pl-p">;</span>
<span class="pl-kt">int</span> <span class="pl-n">n</span><span class="pl-p">,</span> <span class="pl-n">cost</span><span class="pl-p">[</span><span class="pl-n">maxn</span><span class="pl-p">],</span> <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">maxn</span><span class="pl-p">][</span><span class="pl-mi">3</span><span class="pl-p">];</span>
<span class="pl-kt">bool</span> <span class="pl-n">root</span><span class="pl-p">[</span><span class="pl-n">maxn</span><span class="pl-p">];</span>
<span class="pl-n">vector</span><span class="pl-o">&lt;</span><span class="pl-kt">int</span><span class="pl-o">&gt;</span> <span class="pl-n">G</span><span class="pl-p">[</span><span class="pl-n">maxn</span><span class="pl-p">];</span>

<span class="pl-kt">void</span> <span class="pl-nf">dfs</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">u</span><span class="pl-p">)</span> <span class="pl-p">{</span>
    <span class="pl-kt">int</span> <span class="pl-n">_min</span> <span class="pl-o">=</span> <span class="pl-mh">0x3f3f3f3f</span><span class="pl-p">;</span>
    <span class="pl-k">for</span> <span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-nl">v</span> <span class="pl-p">:</span> <span class="pl-n">G</span><span class="pl-p">[</span><span class="pl-n">u</span><span class="pl-p">])</span> <span class="pl-p">{</span>
        <span class="pl-n">dfs</span><span class="pl-p">(</span><span class="pl-n">v</span><span class="pl-p">);</span>
        <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">u</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span> <span class="pl-o">+=</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span> <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]),</span> <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]);</span>
        <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">u</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]</span> <span class="pl-o">+=</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span> <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]);</span>
        <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">u</span><span class="pl-p">][</span><span class="pl-mi">2</span><span class="pl-p">]</span> <span class="pl-o">+=</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span> <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]);</span>
        <span class="pl-n">_min</span> <span class="pl-o">=</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">_min</span><span class="pl-p">,</span> <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span> <span class="pl-o">-</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span> <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]));</span>
    <span class="pl-p">}</span>
    <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">u</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">]</span> <span class="pl-o">+=</span> <span class="pl-n">cost</span><span class="pl-p">[</span><span class="pl-n">u</span><span class="pl-p">];</span>
    <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">u</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">]</span> <span class="pl-o">+=</span> <span class="pl-n">_min</span><span class="pl-p">;</span>
<span class="pl-p">}</span>

<span class="pl-kt">int</span> <span class="pl-nf">main</span><span class="pl-p">()</span> <span class="pl-p">{</span>
    <span class="pl-n">ios</span><span class="pl-o">::</span><span class="pl-n">sync_with_stdio</span><span class="pl-p">(</span><span class="pl-nb">false</span><span class="pl-p">);</span>
    <span class="pl-n">cin</span> <span class="pl-o">&gt;&gt;</span> <span class="pl-n">n</span><span class="pl-p">;</span>
    <span class="pl-k">for</span> <span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span> <span class="pl-o">=</span> <span class="pl-mi">1</span><span class="pl-p">;</span> <span class="pl-n">i</span> <span class="pl-o">&lt;=</span> <span class="pl-n">n</span><span class="pl-p">;</span> <span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">)</span> <span class="pl-p">{</span>
        <span class="pl-kt">int</span> <span class="pl-n">u</span><span class="pl-p">,</span> <span class="pl-n">c</span><span class="pl-p">,</span> <span class="pl-n">m</span><span class="pl-p">,</span> <span class="pl-n">v</span><span class="pl-p">;</span>
        <span class="pl-n">cin</span> <span class="pl-o">&gt;&gt;</span> <span class="pl-n">u</span> <span class="pl-o">&gt;&gt;</span> <span class="pl-n">c</span> <span class="pl-o">&gt;&gt;</span> <span class="pl-n">m</span><span class="pl-p">;</span>
        <span class="pl-n">cost</span><span class="pl-p">[</span><span class="pl-n">u</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-n">c</span><span class="pl-p">;</span>
        <span class="pl-k">while</span> <span class="pl-p">(</span><span class="pl-n">m</span><span class="pl-o">--</span><span class="pl-p">)</span> <span class="pl-p">{</span>
            <span class="pl-n">cin</span> <span class="pl-o">&gt;&gt;</span> <span class="pl-n">v</span><span class="pl-p">;</span>
            <span class="pl-n">root</span><span class="pl-p">[</span><span class="pl-n">v</span><span class="pl-p">]</span> <span class="pl-o">=</span> <span class="pl-nb">true</span><span class="pl-p">;</span>
            <span class="pl-n">G</span><span class="pl-p">[</span><span class="pl-n">u</span><span class="pl-p">].</span><span class="pl-n">push_back</span><span class="pl-p">(</span><span class="pl-n">v</span><span class="pl-p">);</span>
        <span class="pl-p">}</span>
    <span class="pl-p">}</span>
    <span class="pl-k">for</span> <span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span> <span class="pl-o">=</span> <span class="pl-mi">1</span><span class="pl-p">;</span> <span class="pl-n">i</span> <span class="pl-o">&lt;=</span> <span class="pl-n">n</span><span class="pl-p">;</span> <span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">)</span> <span class="pl-p">{</span>
        <span class="pl-k">if</span> <span class="pl-p">(</span><span class="pl-o">!</span><span class="pl-n">root</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">])</span> <span class="pl-p">{</span>
            <span class="pl-n">dfs</span><span class="pl-p">(</span><span class="pl-n">i</span><span class="pl-p">);</span>
            <span class="pl-n">cout</span> <span class="pl-o">&lt;&lt;</span> <span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">][</span><span class="pl-mi">0</span><span class="pl-p">],</span> <span class="pl-n">dp</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">][</span><span class="pl-mi">1</span><span class="pl-p">])</span> <span class="pl-o">&lt;&lt;</span> <span class="pl-n">endl</span><span class="pl-p">;</span>
            <span class="pl-k">break</span><span class="pl-p">;</span>
        <span class="pl-p">}</span>
    <span class="pl-p">}</span>
    <span class="pl-k">return</span> <span class="pl-mi">0</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
</cpde></pre></div>